bitcoinjs-message

Forked from bitcoinjs-message. Published to npm as @bitcoinerlab/btcmessage.

Examples (Note about Electrum support at the bottom)

var tinysecp = require('tiny-secp256k1');
var MessageFactory = require('@bitcoinerlab/btcmessage').MessageFactory;
var toBase64 = require('uint8array-tools').toBase64;
var bitcoinMessage = MessageFactory(tinysecp);

Breaking change in v4: this library is Uint8Array-first and does not return Buffer instances.

sign(message, privateKey, compressed[, network.messagePrefix, sigOptions])

• If you pass the sigOptions arg instead of messagePrefix it will dynamically replace.
• sigOptions contains two attributes
  • segwitType should be one of 'p2sh(p2wpkh)' or 'p2wpkh'
  • extraEntropy will be used to create non-deterministic signatures using the RFC6979 extra entropy parameter. R value reuse is not an issue.

Sign a Bitcoin message

var keyPair = ECPair.fromWIF(
  'L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1',
);
var privateKey = keyPair.privateKey;
var message = 'This is an example of a signed message.';

var signature = bitcoinMessage.sign(message, privateKey, keyPair.compressed);
console.log(toBase64(signature));
// => 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

To produce non-deterministic signatures you can pass an extra option to sign()

var { randomBytes } = require('crypto');
var keyPair = ECPair.fromWIF(
  'L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1',
);
var privateKey = keyPair.privateKey;
var message = 'This is an example of a signed message.';

var signature = bitcoinMessage.sign(message, privateKey, keyPair.compressed, {
  extraEntropy: randomBytes(32),
});
console.log(toBase64(signature));
// => different (but valid) signature each time

Sign a Bitcoin message (with segwit addresses)

// P2SH(P2WPKH) address 'p2sh(p2wpkh)'
var signature = bitcoinMessage.sign(message, privateKey, keyPair.compressed, {
  segwitType: 'p2sh(p2wpkh)',
});
console.log(toBase64(signature));
// => 'I9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

// P2WPKH address 'p2wpkh'
var signature = bitcoinMessage.sign(message, privateKey, keyPair.compressed, {
  segwitType: 'p2wpkh',
});
console.log(toBase64(signature));
// => 'J9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

Sign a Bitcoin message using a Signer interface.

var keyPair = ECPair.fromWIF(
  'L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1',
);
var privateKey = keyPair.privateKey;
var message = 'This is an example of a signed message.';

var secp256k1 = require('tiny-secp256k1');
// Notice we are using the privateKey var from the outer scope inside the sign function.
var signer = {
  signRecoverable: (hash, extraData) =>
    secp256k1.signRecoverable(hash, privateKey, extraData),
};

var signature = bitcoinMessage.sign(message, signer, keyPair.compressed);
console.log(toBase64(signature));
// => 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

signAsync(message, privateKey, compressed[, network.messagePrefix, sigOptions]) Same as sign, except returns a promise, and can accept a SignerAsync interface instead of privateKey

Sign a Bitcoin message asynchronously

var keyPair = ECPair.fromWIF(
  'L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1',
);
var privateKey = keyPair.privateKey;
var message = 'This is an example of a signed message.';

bitcoinMessage
  .signAsync(message, privateKey, keyPair.compressed)
  .then(signature => {
    console.log(toBase64(signature));
  });
// => 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

Sign a Bitcoin message asynchronously using SignerAsync interface

var keyPair = ECPair.fromWIF(
  'L4rK1yDtCWekvXuE6oXD9jCYfFNV2cWRpVuPLBcCU2z8TrisoyY1',
);
var privateKey = keyPair.privateKey;
var message = 'This is an example of a signed message.';

var secp256k1 = require('tiny-secp256k1');
// Note that a Signer will also work
var signerAsync = {
  signRecoverable: (hash, extraData) =>
    Promise.resolve(secp256k1.signRecoverable(hash, privateKey, extraData)),
};
var signer = {
  signRecoverable: (hash, extraData) =>
    secp256k1.signRecoverable(hash, privateKey, extraData),
};

bitcoinMessage
  .signAsync(message, signerAsync, keyPair.compressed)
  .then(signature => {
    console.log(toBase64(signature));
  });
// => 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='
bitcoinMessage
  .signAsync(message, signer, keyPair.compressed)
  .then(signature => {
    console.log(toBase64(signature));
  });
// => 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='

verify(message, address, signature[, network.messagePrefix, checkSegwitAlways])

Verify a Bitcoin message

var address = '1F3sAm6ZtwLAUnj7d38pGFxtP3RVEvtsbV';

console.log(bitcoinMessage.verify(message, address, signature));
// => true

About Electrum segwit signature support

• For Signing: Use the non-segwit compressed signing parameters for both segwit types (p2sh-p2wpkh and p2wpkh)
• For Verifying: Pass the checkSegwitAlways argument as true. (messagePrefix should be set to null to default to Bitcoin messagePrefix)

LICENSE MIT